For the last two postseasons, the coaching staff has paired Zdeno Chara and Dennis Seidenberg as an ace shutdown duo. This year, while Chara and Seidenberg have played together in stretches — the two strongmen have been paired late in games when the Bruins have led — they have not been a regular duo.

Most recently, Chara has been taking the majority of his shifts alongside Dougie Hamilton. Seidenberg has been paired with Matt Bartkowski.

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If Chara and Seidenberg are reunited, Bartkowski, Andrew Ference, and Aaron Johnson are left-shot defensemen in the mix for playoff minutes. Ference is the only sure thing. Bartkowski and Johnson have been healthy scratches.

Ference could skate with Johnny Boychuk on the No. 2 pairing. Hamilton would be the right-side defenseman on the third duo. The Bruins would prefer a veteran defenseman over Bartkowski and Johnson in the playoffs.

Streit has five goals and 13 assists in 36 games while averaging 24:06 of ice time per appearance. The Bruins explored signing Streit as a free agent in 2008. Instead, they signed fellow ex-Canadien Michael Ryder on July 1, 2008.

The Islanders have not been successful at signing Streit to an extension.

If New York’s asking price is too high, the Bruins will look for a more inexpensive depth defenseman. They’ve added Jagr and Kaspars Daugavins. They could add Carl Soderberg once the Swedish forward’s playoff run with Linkoping is over.

“There are some forwards that are going to be in the mix, so I’m probably leaning more toward defense,” GM Peter Chiarelli said. “But I’m happy with our defense as it stands.

Kelly, McQuaid skate

Before their teammates hit the TD Garden sheet for their morning skate Tuesday, center Chris Kelly (broken left tibia) and defenseman Adam McQuaid (strained left shoulder) held an on-ice session. Strength and conditioning coach John Whitesides led Kelly and McQuaid through the paces. Neither participated in the full morning skate.

Of the two, Kelly is most likely closer to returning. The Bruins projected McQuaid to miss 4-6 weeks after he suffered his injury March 19. The team did not estimate Kelly’s recovery time.

Daugavins hits ice

Daugavins participated in warm-ups but did not play against his former team. The Bruins claimed Daugavins on waivers from Ottawa last Wednesday.

The native of Riga, Latvia, didn’t arrive in Boston until Tuesday, when he acquired his work visa. Daugavins will add depth to the team’s penalty kill and bottom-six attack.

Daugavins will wear No. 16.

“I think he’s got a lot of elements to his game that are consistent or compatible with our game,” Chiarelli said. “He’s strong. I think he’s skilled. For whatever, he wasn’t applying a lot. He didn’t fit in there, so that’s fine. So we’ll see where he fits.”

Two for Khudobin

Anton Khudobin, coming off a 2-0 shutout of Buffalo on Sunday, was in goal against the Senators for the second straight game. It was the second time he made back-to-back starts. The first time Khudobin started consecutive games, he was pulled in the second match after allowing three goals to the Maple Leafs in the Bruins’ 3-2 loss on March 23. The Bruins have 13 games remaining in a 23-day span. Khudobin will be Tuukka Rask’s backup in the playoffs. But Khudobin should see at least three more starts to keep Rask fresh for the postseason. “Both goaltenders are going to get their fair share of games,” Julien said. “We have to keep moving forward here. This month here is not going to be any easier than March. So both guys are going to be utilized.” . . . Niklas Svedberg was named the AHL Rookie of the Month Tuesday. The Providence goalie went 7-1-0 with a 1.95 goals-against average and a .933 save percentage in March. Svedberg projects to be Rask’s backup next season . . . Hamilton missed a shift after colliding with Erik Condra in the Bruins zone in the third period. Hamilton returned and finished the game . . . Tyler Seguin was credited with a game-high 12 shots.

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